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Need some suggestion how to PP noise

Discussion in 'Astrophotography' started by tg9413, Aug 17, 2015.

  1. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    I was at death valley over weekend and tried to take some shots of the amazing night sky over there. One thing right off the bat I really once the sun is set is that the extreme hot weather there is causing my GX7 to have unbelievable high amount of noise, it was about 110F around sun set and the temp is still about 100F around 10ish at night. I took a 20sec long exposure without long exposure noise reduction, about half of the photo around the frame is filled with red pix.
    Here is a sample took with long exposure noise reduction and messing with the noise reduction in LR. Shot is taken at 1600iso and 20sec exposure, as you can see, even after crank the luminace way high before it start to rubbery, the pic still filled with noise and looks grainy.
    I don't have any identical photo to stack with right now, but I do have some photo taken around the same time frame. What are some of the PP technique or software I can use to reduce the noise further or even before I start post process in LR?

    Also, for anyone that has experience in shooting under extreme heat, what can be done to at least help to cool off the camera a bit? or we really need a low res high end camera like the A7s? I don't think weather seal actually helps in this situation. The camera body itself is just hot right after I pull it out of my bag. Timelapse or star trail could be very problematic in situation like this. the dark frame are not accurate cuz the temp change quiet rapidly, and you can't really use long exposure NR in those.
     

    Attached Files:

  2. siftu

    siftu Mu-43 Top Veteran

    633
    Mar 26, 2015
    Bay Area, CA
    siftu
    That does have a lot of noise, quite surprising for iso 1600!. Not sure if you are willing to post the RAW up for us to play with?
     
  3. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Here is the link to the raw file
    https://drive.google.com/file/d/0B7eB9t_5IycnNlhtY3p0bDE1UlE/view?usp=sharing

    the noise is horrible, and the only thing I can think of is the heat. I may have introduced quiet a bit noise during PP from increasing contrast and clarity. But I was at a lake the night before that which was cold enough that I had to wear a jacket, and the photo taking under iso3200 had way less noisy than this one here :/
     
    Last edited: Aug 17, 2015
  4. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi,

    Yes, heat will make noise much worse.

    1. how often are you taking dark frames?

    2. try setting your RAW processor to B&W, reduce the NR to 0, then adjust the Luminance NR to taste, turn B&W off, and adjust the Chrominance NR.

    Barry
     
  5. agentlossing

    agentlossing Mu-43 Hall of Famer

    Jun 26, 2013
    Andrew Lossing
    Why aren't you using long exposure NR?
     
  6. siftu

    siftu Mu-43 Top Veteran

    633
    Mar 26, 2015
    Bay Area, CA
    siftu
    I originally misread and thought he DID use NR.. This was most definitely the biggest problem, there are what look to be hot pixels all over.
     
  7. tg9413

    tg9413 Mu-43 Regular

    76
    Mar 12, 2014
    Actually, this is taken with NR :( the one without the NR is totally unusable, 1/2 of the pic was covered in red pix.

    Edit:
    this is the pic that was taken without the NR
    https://drive.google.com/file/d/0B7eB9t_5IycnamM2d3Zvck83SmM/view?usp=sharing
     
    Last edited: Aug 17, 2015